My earlier patent application, Ser. No. 814,388, filed July 11, 1977, now U.S. Pat. No. 4,138,847, describes a class of heat engines employing a constant volume heat recuperator having two branches arranged to transfer heat between working medium confined in a moving constant volume chamber orbiting in one cavity and working medium confined in another moving constant volume chamber that orbits in the opposite direction in a second cavity. The heat recuperator utilizes heat transfer means such as heat pipes within the walls of the cavities to effect an exchange of heat between the working medium in the two cavities. That arrangement causes the hotter working medium to be cooled at constant volume as it is swept through one cavity and causes the cooler working medium to be heated at constant volume as it is swept through the other cavity.
This application describes an improvement on the recuperator devices disclosed in my earlier patent application. All of the embodiments disclosed in that earlier application employ some type of rotary positive displacement mechanism in the recuperator which requires a blocking means within each cavity to prevent the gas that has been recuperatively heated or cooled in a rotating constant volume chamber from being swept around again and again in the same orbit. Associated with the rotary positive displacement mechanisms disclosed in my earlier application is the problem of preventing or minimizing leakage of the confined working medium back to the intake side of the cavity. All of the rotary positive displacement mechanisms there disclosed either utilize orbiting radially sliding vanes that are drawn out of the way into pockets in a rotor as the vanes approach a blocking means fixed in the cavity or utilize pistons orbiting in a fixed circular path and a slidable blocking means in the cavity that is retracted out of the path as each of the orbiting pistons nears the blocking means. Thus, in addition to the rotary motion of the vanes or pistons, both those types of positive displacement mechanisms require an additional sliding motion by either the vanes or the blocking means and consequently the arrangements are somewhat more mechanically complex than would be the case if only purely rotary motion occurred.